With a multidisciplinary approach using methods of clinical opthalmology, electrophysiology, experimental pathology and biochemistry, we propose to study an here-to unreported inherited dystrophy of the retina in the Collie dog. We have observed the behavioral changes in these dogs and correlated the ophthalmoscopic and electrophysiological changes of their retinas. We are currently doing detailed light and electron microscopic studies of the retina to examine the relationship between the rod and cone degeneration, eye pigmentation and regional differences of the retina. We are in the process of studying the level of cyclic-GMP and the activity of phosphodiesterase in the retina during the various phases of retinal dystrophy.